Key takeaways
Montelukast (Singulair) and levocetirizine (Xyzal Allergy) are both used to treat allergy symptoms, but they work in different ways and have different uses. Montelukast is a leukotriene receptor antagonist that helps manage asthma and prevent exercise-induced asthma, in addition to treating seasonal and year-round allergies. It is available only by prescription and comes in various forms, including tablets, chewable tablets, and granules. Levocetirizine, on the other hand, is an antihistamine that blocks histamine to relieve allergy symptoms and chronic hives. It is available both over-the-counter and by prescription, and comes as tablets and a liquid. Both medications are usually taken once daily in the evening. Montelukast does not cause drowsiness, whereas levocetirizine can make you sleepy. Additionally, montelukast has a risk of serious mental health side effects, while levocetirizine's main risk is a potential accidental overdose, especially if taken with other antihistamines.
